DIY Rally 2007 Runners-Up, Part 2: Beaten by the Multimachine

It was tough to pick the best, wildest, most creative reader projects of the year, but Pat Delany's multimachine blew us away. Here are four similar hand-operated machine submissions that didn't quite make the cut.

Ben has been running a Wi-Fi system for years with his homemade green transmitter, which forms a single node in an expansive neighborhood hotspot in San Diego, Calif. The "green" title comes from the transmitter's ability to dock with a rooftop solar mount and deliver Wi-Fi coverage without any power pulled from the grid. An internal battery even keeps users surfing for 12 hours after sunset. Ben built the node using Meraki hardware with a few additions of his own. By substituting a more powerful amplifier and antenna, he says he has made the node produce a signal 40 times more powerful than with the original hardware, but just under the legal limit of four watts. Ben implemented MIT's Roofnet software to link up with the other nodes in his neighborhood.

High energy prices motivated Kel Smith to built this DIY log splitter. Unlike a commercial version, it doesn't use brute force from hydraulics to split logs. Instead, it uses a threaded rod to produce linear motion and an electric motor to move a splitting wedge like a jackhammer. An eccentric cam strikes the wedge 10 times per second, moving it back and forth less than an inch. An operator feeds in a log and sets the machine to move forward, just as he or she would with a conventional splitter.

Kel says the advantages of the device are numerous. For one, the motor needed for Kel's splitter can be much less powerful than one needed for its hydraulic equivalent. A ¾ HP electric motor or 3 HP gasoline engine is enough to do the job, where a hydraulic splitter would require 8-10 HP. If an electric motor is chosen, the machine is also much quieter than its smoke-spewing equivalent - it only makes noise when the wedge is actually striking a log. Kel says it's also safer, since the wedge is mounted on a spring, and applies force to the log gradually before it actually starts striking. Finally, the lower forces involved mean an H-beam is strong enough to hold everything together.

Although the pendular crankshaft has been in use for over 200 years, Rudloph Draaisma still saw room for improvement. The conventional way of transmitting power - which is used in almost all piston engines - causes considerable vibration and wear from the oscillating masses and side forces exerted on the piston. Rudolph says that his linear crankshaft eliminates these side forces through a unique configuration of rotating elements. The result is reduced vibration, better sealing capacity for the piston rings, and significantly reduced wear.

Tim Anderson got the inspiration for his hand-cranked paper shredder when he ran across a pile of discarded shredder parts. Originally, he planned to power the shredder with bicycle pedals, but after attaching a hand crank and testing it out, he deciding the satisfaction of shredding documents by hand was even better. To make it usable, Tim welded the shredder to a pair of heavy-duty drawer slides to mount it underneath a counter, where it can be pulled out to feed on junk mail, tax forms, and whatever other irritating documents fall into its jaws.

Hanging a bike from a garage ceiling with traditional J-shaped hooks takes a bit of finagling, so MIT doctoral student Craig Forest built this improved claw for bike storage. It works like a retractactable ball-point pen. You can click the black button with your bike and the claw clamps down. The same vertical motion releases the claw, and it will stay open until you re-click to hang your bike again. Craig built the first prototype of the claw while he was an undergraduate at Georgia Tech. He continues improving it on weekends, using the lab where he works during the week developing medical devices and doing biological research.